Photos: NAsA. ARt: LAWsoN PARKER,
NGM stAFF. souRcE: NAsA
Seasonal Flux It’s not only Earth
that has a winter, spring, summer, and fall. “Anything
with an atmosphere has seasons,” says NAsA’s Jim
Green. they just look different on other celestial bodies.
Equinoxes and solstices mark the change in seasons,
and rotation, orbit, distance from the sun, and axial
tilt all play a role in how weather shifts play out. When
Pluto is farthest from the sun—winter—its atmosphere
collapses. saturn’s rings don’t cast shadows during
equinoxes. on its moon titan, spring showers are made
of methane and can last for several Earth years. Winter
on Mars brings carbon dioxide snow. Mercury, notably,
remains nearly seasonless—due to a thin atmosphere
and a rotation so slow that one of its days is equal to
the length of two of its years.
—Johnna Rizzo
*Length of each season varies slightly.
NEXT
Winter
Each ring
=
one Earth
year
Outer rings =
current season in
Northern Hemisphere
Closest
to the sun
Farthest
from the sun
Axis tilt: Less tilt
means smaller
seasonal changes.
Spring
Jupiter, Venus, and
Mercury have little
seasonal variation.
NEPTUNE
41 years
Length of
one season*
MARS
7 months
EARTH
90 days
VENUS
MERCURY
JUPITER
SATURN
8 years
URANUS
21 years
Length of
one year
Length of
current
season
January
2014